The present invention relates to a cooling structure for an internal combustion engine.
Cooling structures for cooling engines, lubricant oil, transmission oil, fuel, charged air and/or EGR fluids are associated with radiators or heat exchangers. In modern vehicles space is becoming more and more critical, i.e., there is a need for compacting the accessories belonging to an internal combustion engine due to very restricted space available. Engine compartment space is especially critical for heavy vehicles where every cm required for the engine and its accessories may intrude on the available space for other features on the heavy vehicle, or even worse intruding on the total stowage space.
For instance, a conventional EGR cooling structure comprises EGR pipes, coolant pipes and an EGR cooler. The EGR cooler as such is for a heavy vehicle approximately 5 dm3 and has a weight of 15 kg. The EGR cooling structure is traditionally arranged in the vicinity of an exhaust manifold of the internal combustion engine, i.e., to the left or the right side of an engine block. It is necessary to provide space for installing such EGR cooling structure and/or charge air cooling structure and/or lubricant oil cooling structure and/or transmission oil cooling structure and/or fuel cooling structure in the engine compartment together with other components provided on or beside said engine. However, with the decreasing space available this has proven to be a problem.
It is desirable to provide a cooling structure in addition to the internal combustion engine coolant system which is more compact compared to the conventional structures.
According to a first aspect of the invention it is provided a cooling structure for cooling an liquid-cooled internal combustion engine where said engine comprises an EGR passage interposed between an exhaust manifold structure and an inlet manifold structure of said engine, said cooling structure comprising a first cooling system and a second cooling system, where said first cooling system comprises at least one radiator and a liquid coolant circulatable through said radiator and said internal combustion engine for cooling said internal combustion engine, characterized in that a flywheel housing for said internal combustion engine is provided with at least a portion of said second cooling system.
An advantage of this aspect is that the installation is compact and utilizes unused space provided in or by said flywheel housing.
Another advantage with said embodiment is that it may save weight compared to conventional assemblies.
In another example embodiment said second cooling system comprises at least one heat exchanger for cooling one or more of the following: charged intake air, lubricant engine oil, transmission oil, fuel, exhaust gases.
An advantage with said example embodiment is that space requiring heat exchangers may be provided at least partially in said flywheel housing.
In another example embodiment a cooler in said second cooling system is provided as a separate unit inside said flywheel housing.
An advantage with said example embodiment is that the manufacturing cost may be minimized together with a very compact design.
In still another example embodiment said cooler in said second cooling system is at least partially integrated in said flywheel housing.
An advantage of this embodiment is that the second cooling system can be even further compacted and total weight may be reduced.
In yet another example embodiment said flywheel housing is provided with cooling fins on the inside and/or the outside of said flywheel housing.
An advantage with this embodiment is that the flywheel housing may be used as a cooler itself.
In still another example embodiment at least a portion of an EGR passage and/or fuel passage and/or transmission oil passage and/or lubricant engine oil passage and/or charged intake air passage is integrated in said flywheel housing.
An advantage of this embodiment is that only short passages for said fluids may be needed outside the flywheel housing which may decrease the risk of leakage and further decreases the need of space. Another advantage is that total weight may be decreased.
In still another example embodiment of the present invention at least a portion of a liquid coolant passage is integrated in said flywheel housing.
An advantage with this embodiment is that only short liquid coolant passages are needed outside the flywheel housing which may decrease the risk of leakage and further decreases the need of space. Another advantage is that total weight may be decreased.
In still another example embodiment of the present invention a pump for circulating said liquid coolant is provided in said flywheel housing.
An advantage of this embodiment is that the space needed for an external pump may be used for other purposes.
In still another example embodiment said pump is mechanically driven by a belt from a flywheel.
An advantage with this embodiment is that no external driving means outside the flywheel is needed for pumping the liquid coolant.
In still another example embodiment of the present invention said pump is electrically driven.
An advantage with this embodiment is that the pump may be oriented at any available position in said flywheel housing without taking into account any mechanical driving means such as the flywheel.
In still another example embodiment of the present invention said pump is driven by a gearwheel connectable to the flywheel.
An advantage with this embodiment is that the teeth that may be available on the outer periphery of the flywheel to be connectable with the starting device may also be used for driving the pump.
In yet another example embodiment of the present invention said first and second cooling system is connected in series and uses the same liquid coolant.
An advantage with this embodiment is that one single liquid coolant may be used.
In still another example embodiment of the present invention said first and second cooling system is connected in parallel and uses the same liquid coolant.
An advantage with this embodiment is that liquid coolant from one system do not affect the other system.
in still another example embodiment of the present invention said first and second cooling systems are two separate cooling systems with separate liquid coolants.
An advantage of this embodiment is that the two systems are totally independent of each other.